Naslov
Climate changes in Upper Pleistocene, isotope data from loess malakofauna

Autori
Banak, Adriano, Sprovieri, Mario ; Lirer, Fabrizio ; Mandic, Oleg ; Pavelić, Davor ; Ferić, Pavle

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Earth system evolution and the Mediterranean area from 23Ma to the present : abstract book / Barbieri, Francesco - Parma : Istituto per l'Ambiente Marino Costiero, Università degli Studi di Parma, 2009, 45-45

Skup
13th Congress of Regional Committee on Mediterranean Neogene Stratigraphy (RCMNS)

Mjesto i datum
Napulj, Italija, 02.09.2009. - 06.09.2009

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
loess; gastropods; stable isotope; Pleistocene; climate

Sažetak
Bansko brdo hill is situated in eastern part of Croatia, in Baranja region, between rivers Danube, Drava and Hungary in north. Geological basement and core of Bansko brdo hill consists of Miocene sediments, mainly limestones, sandstones wih connglomerates (sandstone and limestone pebels) and igneous rocks ; andesite and basalt (Jenko, K., 1957-1959). Pleistocene loess covers that sediments. It is eolyc, silt size grain sediment, deposited during glacial (cold and arid) periods in Pleistocene. It was deposited by strong winds (dominantly northern) on big open graslands and steps. Smaller part of loess in Baranja region was deposited in marshes and other aquatic enviroments. It is chemicaly altered and called 'marsh loess'. Total estimated thicknes of loess in investigated area is aprox. 32m. Paleontological and isotope data from loess section at Bansko brdo hill provide records for climate variations in the upper Pleistocene of SE Europe. Thickest (northern) profile from which samples were taken is aprox. 24m and thiner (southern) is aprox. 19m. Both southern and northern loess profile, are marked with 1m thick paleosoils, which can be corelated, but with care. Totaly 30 samples were analysed for isotope, paleontological and sedimentological data. Loess profiles are rich in gastropod fauna, which is dominantly land biostrata. Gastropod shells from 3 most abundand species (Helicopsis hungarica, Chondrula tridens and Arianta arbustorum) were analysed on stable isotopes ΔO18 and ΔC13 in IAMC-CNR in Naples. That species indicate arid climate, while other two abundant species: Orcula dolium and Succinea oblonga ; indicate humid one. Isotope results from loess sections, suggest a slight arid/humid and cold/warm variations in climate, during upper pleistocene. Average value of ΔO18 and ΔC13 indicate cold and arid climate and small variations within. Periods of arid and warm climate are equally long as humid an cold one. Most abundand from 13 species is Helicopsis striata, gastropod tipical for open and arid habitats (graslands and sunny foothills). The high relative percentage of arid gastropod taxa in the northern loess sections, indicates arid climate for this area, with shorter periods of colder and more humid climate. In southern profile, percentage of taxa that represent humid and colder climate is higher. Problem in this research is interpretation of isotope values obtained from fossil land gastropod shells. However, corelation between results obtained from land gastropods and marine core samples (from Mediterranean sea), can be made, with some slight alterations. Next step in isotope studies on land gastropods, would be corelation of results from fossil gastropods and recent gastropods. Isotope results (from recent gastropods) associated with recent data on average annually temperature and humidity, can provide us a certain standard. Comparing that 'standard' with isotope results, from fossil gastropods, can give us relative values for temperature and humidity in upper Pleistocene. That could be useful tool for reconstructing climate changes in more precise scale and help researches to predict future climate changes. In the end, this study presents a climate inudced changes in taxonomy of gastropods, which is probably expression of Milankovitch's 41-ky cycles (Kukla, G., 2005.).

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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